Communication technique for controlling crane operations

ABSTRACT

A communication system for controlling a mobile vehicle comprising a trolley system transmitting communication signals between an on-board station carried by said vehicle and a command station and including photoelectric coupling means serving to pass signals between said trolley system and said stations, while electrically isolating said stations from said trolley system.

ite tates Patent 1191 2 qSCHMlTTl messy Pease May 22, 1973 [54]CUMMUNICATION TECHNIQUE FOR 3,552,692 1 1971 Horeczky ..246/l87 B C ONTRLLING RANE PERATI N 0 C O 0 S OTHER PUBLICATIONS [75] Inventor: Logan L.Pease, Bountiful, Utah IBM Technical Disclosure Bulletin Vol. 13, No. 3Asslgnee! Eaton Corporation, Cleveland, Ohl0 Page 680 August, 1970Circuit Condition Indica- 22 Filed: July 22,1971 Carey 6131- [21 Appl.No.: 1653296 Primary ExaminerDonald J Yusko Attorney-Lynn G. Foster [52]US. Cl .340/147 R, 246/187 B [57] ABSTRACT [51] Int. Cl. ..B6ll 3/0 1),H03k 17/56 58 Field of Search ..307/9,114,311; A Communication Systemfor controlling a mobile 191/1 4; 340/47 246/167, 187; vehiclecomprising a trolley system transmitting com- 256/106 217 S H5/72 82munication signals between an on-board station carried by said vehicleand a command station and in- [56] References Cited cludingphotoelectric coupling means serving to pass signals between saidtrolley system and said stations, UNITED STATES PATENTS whileelectrically isolating said stations from said trolley system. 3,315,1764/1967 Biard ..250/2l7 X 3,594,572 7/1971 Horeczkyn ..246/ 182 R 7Claims, 2 Drawing Figures 7 T I l l l +sv l i l l 1- *1 I 1 1 287 1 l l1 l 8 1 l i[ l 5v. l L 34 J V RETURN I T 1 6 s01 l |SCHM|TT 3 l I 1 l ll l l COMMAND STATION RECEIVE ,27' J ON BOARD STATION PATENTEU B I3,735,352

I SHEET 2 0r 2 Z8\(COMMUNICATIONS) r 4 a 32 (GRND. (PHASE 2) 46(PHASE 1) 4-4B PHASE 3) i COMMUNICATION TECHNIQUE FOR CONTROLLING CRANEOPERATIONS BACKGROUND 1. Field of Invention This invention relates tocommunication systems and is particularly directed to communicationsystems for controlling the operations of stacker cranes and the like.

2. Prior Art In recent years, the trend toward automation orcomputerized control has touched virtually every area of factory andwarehouse operations and the like. However, no satisfactory system hasbeen proposed, heretofore, for communicating with mobile vehicles, suchas stacker cranes and the like. Because of the large amounts of iron andsteel in such buildings and electrical noise generated by machinesoperating in the vicinity, radio communications are unreliable. On theother hand, the use of ribbon wires and umbilical cords restricts themobility of such vehicles and is subject to disruption of communicationsdue to damage or severance of the wire or cable.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION These disadvantages of theprior art are overcome with the present invention and a communicationssystem is proposed which is simple and reliable, which is compatiblewith either manual or computerized control, and which is substantiallyunaffected by electrical noise in the vicinity.

The advantages of the present invention are preferably attained byproviding a communications system employing a trolley system having anextra conductor in the trolley power rail and sharing the groundconductor between the power and communication systems, together withnovel circuitry for transmitting and receiving communications employingphotocoupling techniques for noise isolation.

Accordingly, it is an object of the present invention to provideimproved communication system for vehicles, such as stacker cranes andthe like.

Another object of the present invention is to provide communicationsystems for vehicles, such as stacker cranes and the like, which aresubstantially unaffected by electrical noise.

An additional object of the present invention is to providecommunication systems for vehicles, such as stacker cranes and the like,which are compatible with either manual or computerized control.

A specific object of the present invention is to provide communicationsystems for vehicles, such as stacker cranes and the like, employing atrolley system having an extra conductor in the trolley power rail andsharing the ground conductor between the power and communicationsystems, together with novel circuitry for transmitting and receivingcommunications employing photocoupling techniques for noise isolation.

These and other objects and features of the present invention will beapparent from the following detailed description, taken with referenceto the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammaticrepresentation of a communication system embodying the presentinvention; and

FIG. 2 is a transverse section through the trolley power rail of thecommunication system of FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In that form of thepresent invention chosen for purposes of illustration, FIG. 1 shows acommand station 2 and an on-board station 4 coupled by a trolley system6. The on-board station 4 is mounted on the vehicle to be controlled andis connected, through the trolley system 6, to the command station 2,which may be located in substantially any desired location.

As will be seen, the circuits of the command station 2 and on-boardstation 4 are identical. For convenience, the elements of the on-boardstation 4 are identified by primed reference numerals. Thus, eachstation 2 and 4 has a signal input 8 and 8' which is connected throughthe light-emitting diode l0 and 10' of a photocoupling unit 12 and 12'to a suitable voltage source 14 and 14'. The phototransistor 16 and 16,of the photocoupling unit 12 and 12', passes signals to the base of atransistor 18 and 18' which triggers the lightemitting diode 20 and 20of a second photocoupling unit 22 and 22' which causes phototransistor24 and 24' to apply signals to the output 26 and 26'. The collector oftransistor 18 of the command station 2 is also connected to conductor 28of the trolley system 6, while the collector of transistor 18 of theon-board station 4 is connected to brush 30 which slidably engagesconductor 28, as more fully described below. Similarly, the groundedemitter of transistor 18 of the command station 2 is connected toconductor 32 of the trolley system 6, while the grounded emitter oftransistor 18 of the on-board station 4 is connected to brush 34 of thetrolley system 6 which slidably engages conductor 32. It will be seenthat signals passed by either of the transistors 18 or 18' will beapplied, either directly or through trolley conductor 28 and brush 30,to actuate both of the photodiodes 20 and 20'. Hence, a signal at eitherinput 8 and 8' will result in the signal being passed to both outputs 26and 26. However, each station 2 and 4 includes suitable means forignoring the signals originating therein, as indicated at 27 and 27'.

FIG. 2 is a transverse section through the power rail, indicatedgenerally at 40, of the trolley system 6. As shown, the power rail 40comprises an elongated, hollow-duct 42 formed of electrically insulatingmaterial and has five electrically conductive strips 28, 32, 44, 46, and48 spaced about the interior of the duct 42 and extending longitudinallytherein. The duct 42 is disposed adjacent and parallel to all possibleroutes of the controlled vehicle. A trolley 50 travels within the duct42 on wheels 52 and is rigidly connected to the controlled vehicle, notshown, by a hollow pigtail 54 which projects through a slot 56 extendingalong one side of the duct 42. The trolley 50 carries a plurality ofelectrically conductive brushes 30, 34, 58, 60, and 62 which areresiliently urged into electrical contact with the strips 28, 32, 44,46, and 48 by suitable means, such as springs 64. Each of the brushes30, 34, 58, 60, and 62 is connected to a respective conductive wire 66which passes through trolley 50 and pigtail 54 to appropriate componentswithin the controlled vehicle.

In use, strips 44, 46, and 48 of power rail 40 of the trolley system 6each carry electrical power of a respective phase which serves toenergize the motors to propel and actuate the controlled vehicle. Asdescribed above, conductive strip 28 of power rail 40 provideselectrical connection between the command station 2 and on-board station4 of the communication system, vehicle strip 32 provides ground returnfor both the power and communication systems. Command signals for thecontrolled vehicle, such as START, STOP, FORWARD, REVERSE, RAISE, LOWER,rate of speed, etc., are supplied to input 8 of the command station 2and may be originated from either a manual control panel or a suitablecomputer. The signals applied to input 8 cause photodiode 10 to emitlight which causes phototransistor 16 to conduct and this, in turn,causes transistor 18 to conduct. The signals passed by transistor 18will be applied directly to photodiode 20 and will also be appliedthrough conductive strip 28 and brush 30 of the trolley system 6 tophotodiode 20', causing both of the photodiodes 20 and 20' to emitlight. Hence, both phototransistors 24 and 24 will pass the commandsignals. Phototransistor 24 will pass the command signals to output 26'of the on-board station 4 where they will be applied to the appropriatecomponents of the controlled vehicle to cause the vehicle to execute thecommands.

Signals may be applied to input 8 of the on-board station 4 by anyappropriate sensor devices carried by the controlled vehicle to indicatethe condition and location of the controlled vehicle. These signals willbe transmitted by the on-board station 4 and will be passed throughtrolley system 6 and applied to output 26 of the command station, insubstantially the manner described above, and these signals may then bepassed to the computer logic or to appropriate indicators on the manualcontrol panel. It will be seen that, although the trolley system 6 isexposed to electrical noise, the photocoupling units 12, 12', 22 and 22serve to completely isolate such noise from the input and outputcircuits.

Obviously, numerous variations and modifications may be made withoutdeparting from the present invention. Accordingly, it should be clearlyunderstood that the form of the present invention described above andshown in the accompanying drawing is illustrative only and is notintended to limit the scope of the invention.

What is claimed is:

1. A communication system for mobile vehicles comprising:

a command station having an input circuit for transmitting commandsignals to said vehicle and an output circuit for receiving sensorsignals from said vehicle,

an on-board station mounted on said vehicle and having an output circuitfor receiving command signals from said command station and an inputcircuit for transmitting sensor signals to said command station,

a trolley system extending adjacent and parallel to desired routes ofsaid vehicle and serving to transmit driving power to said vehicle andto electrically connect and carry said signals between said commandstation and said on-board station, and

photocoupling means communicating signals between said command stationand said on-board station by transmitting signals to and receivingsignals from said trolley system while electrically isolating the inputand output circuits of said stations from said trolley system.

2. The communication system of claim 1 wherein said command stationcomprises:

input means for signals to be transmitted;

a first photocoupling unit including a first photodiode connected toreceive signals from said input means andserving to emit light signalsindicative of the signals received from said input means, and a firstphototransistor optically coupled to said first photodiode and servingto pass electrical signals indicative of said light signals;

a transistor connected to said first phototransistor and serving to passsaid electrical signals to said trolley system;

a second photocoupling unit including a second photodiode connected toreceive said electrical signals from said trolley system and to emitoptical signals indicative of said electrical signals, and a secondphototransistor optically coupled to said second photodiode and servingto pass electrical output signals indicative of said optical signals;and

output means connected to receive and pass said electrical outputsignals.

3. The communication system of claim 2 wherein:

said on-board station is substantially identical to said command stationin circuit operation.

4. The communication system of claim 2 further comprising:

means for shunting said electrical output signals to ground when signalsare being applied to said input means.

5. The communication system of claim 1 wherein said trolley systemcomprises:

a power rail having an elongated hollow duct composed of electricallyinsulating material and formed with a slot extending longitudinallyalong one side thereof;

five electrically conductive strips mounted in spaced relation withinsaid power rail and extending longitudinally thereof,

a trolley movable within said power rail and having a hollow pigtailextending through said slot of said power rail and connected to saidvehicle,

a plurality of electrically conductive brushes carried by said trolleyand each resiliently urged into electrical contact with a respective oneof said conductive strips, and

a plurality of wire means each connected to a respective one of saidbrushes and extending through said pigtail to respective components ofsaid vehicle.

6. The communication system of claim 5 wherein:

three of said five conductive strips each carry electrical power of arespective phase for energizing the motor of said vehicle,

the fourth of said five conductive strips provides electrical connectionbetween said command station and said on-board station for transmissionof communications therebetween, and

the fifth of said five conductive strips is a ground return line commonto the power system of said vehicle and to said communication system.

7. A communication system for mobile vehicles comprising:

a command station having an input circuit for transmitting commandsignals to said vehicle and an output circuit for receiving sensorsignals from said vehicle,

between said command station and said on-board station by transmittingsignals between said input and output circuits of said stations whileelectrically isolating said stations from external noise.

1. A communication system for mobile vehicles comprising: a commandstation having an input circuit for transmitting command signals to saidvehicle and an output circuit for receiving sensor signals from saidvehicle, an on-board station mounted on said vehicle and having anoutput circuit for receiving command signals from said command stationand an input circuit for transmitting sensor signals to said commandstation, a trolley system extending adjacent and parallel to desiredroutes of said vehicle and serving to transmit driving power to saidvehicle and to electrically connect and carry said signals between saidcommand station and said on-board station, and photocoupling meanscommunicating signals between said command station and said on-boardstation by transmitting signals to and receiving signals from saidtrolley system while electrically isolating the input and outputcircuits of said stations from said trolley system.
 2. The communicationsystem of claim 1 wherein said command station comprises: input meansfor signals to be transmitted; a first photocoupling unit including afirst photodiode connected to receive signals from said input means andserving to emit light signals indicative of the signals received fromsaid input means, and a first phototransistor optically coupled to saidfirst photodiode and serving to pass electrical signals indicative ofsaid light signals; a transistor connected to said first phototransistorand serving to pass said electrical signals to said trolley system; asecond photocoupling unit including a second photodiode connected toreceive said electrical signals from said trolley system and to emitoptical signals indicative of said electrical signals, and a secondphototransistor optically coupled to said second photodiode and servingto pass electrical output signals indicative of said optical signals;and output means connected to receive and pass said electrical outputsignals.
 3. The communication system of claim 2 wherein: said on-boardstation is substantially identical to said command staTion in circuitoperation.
 4. The communication system of claim 2 further comprising:means for shunting said electrical output signals to ground when signalsare being applied to said input means.
 5. The communication system ofclaim 1 wherein said trolley system comprises: a power rail having anelongated hollow duct composed of electrically insulating material andformed with a slot extending longitudinally along one side thereof; fiveelectrically conductive strips mounted in spaced relation within saidpower rail and extending longitudinally thereof, a trolley movablewithin said power rail and having a hollow pigtail extending throughsaid slot of said power rail and connected to said vehicle, a pluralityof electrically conductive brushes carried by said trolley and eachresiliently urged into electrical contact with a respective one of saidconductive strips, and a plurality of wire means each connected to arespective one of said brushes and extending through said pigtail torespective components of said vehicle.
 6. The communication system ofclaim 5 wherein: three of said five conductive strips each carryelectrical power of a respective phase for energizing the motor of saidvehicle, the fourth of said five conductive strips provides electricalconnection between said command station and said on-board station fortransmission of communications therebetween, and the fifth of said fiveconductive strips is a ground return line common to the power system ofsaid vehicle and to said communication system.
 7. A communication systemfor mobile vehicles comprising: a command station having an inputcircuit for transmitting command signals to said vehicle and an outputcircuit for receiving sensor signals from said vehicle, an on-boardstation mounted on said vehicle and having an output circuit forreceiving command signals from said command station and an input circuitfor transmitting sensor signals to said command station, andphotocoupling means for providing communication between said commandstation and said on-board station by transmitting signals between saidinput and output circuits of said stations while electrically isolatingsaid stations from external noise.